The present invention relates to liquid-liquid extraction techniques and more particularly to a process for regenerating an active component of an organic extractant.
Solvent extraction and liquid ion exchange processes for recovering and separating metal values from process solutions are well known in any art. An Example of one such process is disclosed in U.S. Pat. No. 3,224,873. In the process disclosed in this patent, cobalt is separated from nickel process solutions by use of organic extractants comprising .alpha.-hydroxyoximes dissolved in a water immiscible solvent. The cobalt is stripped from the loaded extractant by contact with a strong mineral acid solution. High acid concentrations in both the process and stripping solutions cause degredation of the .alpha.-hydroxyoximes. If the organic extractant contains other acidic components, these components can also cause degradation of the .alpha.-hydroxyoximes. Degradation of the .alpha.-hydroxyoximes in the organic extractant becomes even more of a problem when the extractant is used at elevated temperatures.
Although much attention has been focused on the minimization of losses of active components of the organic extractant to the raffinate and/or to the stripping solution to enhance process economics, little, if any, attention has been directed to the problem of the degradation of active components in the organic extractant and the regeneration thereof.
Heretofore, the problems associated with degradation of active components of the organic extractant have been solved by adding fresh active components to the organic extractant. The addition of fresh active components to the organic extractant does not cure the problem of active component degradation but only maintains the extractive potential of the extractant while incurring reagent costs.